# CVE-2026-29129: Configured cipher preference order not preserved vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.16 through 11.

Source: https://junglewise.ai/threats/cve-2026-29129-apache-tomcat-cipher-preference-order-not-preserved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-09. Updated: 2026-05-20  
License: CC BY 4.0 with a link back

CVE-2026-29129 · Severity: high · CVSS 7.5 · Published 2026-04-09

Apache Tomcat is a widely used web server and application container for Java-based websites. A vulnerability was identified where the server fails to respect the security administrator's preferred order of encryption methods (ciphers). This could allow a connection to use a weaker encryption method than intended, potentially exposing sensitive data to interception.

Technologies: [Apache Tomcat](https://junglewise.ai/threats/technologies/tomcat), [org.apache.tomcat:tomcat (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-tomcat), [org.apache.tomcat:tomcat-coyote (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-tomcat-coyote), [org.apache.tomcat.embed:tomcat-embed-core (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-embed-tomcat-embed-core). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache), [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-29129 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-29129 being exploited in the wild.

**How severe is CVE-2026-29129?** High severity, with a CVSS score of 7.5, published 9 April 2026.

**Which products and versions are affected?** Apache Tomcat 11.0.16 to 11.0.18, 10.1.51 to 10.1.52, 9.0.114 to 9.0.115, 9.0.114 to 9.0.115, 10.1.51 to 10.1.52, 11.0.16 to 11.0.18; org.apache.tomcat:tomcat (Maven) ECOSYSTEM:introduced=9.0.114,fixed=9.0.116; org.apache.tomcat:tomcat-coyote (Maven) ECOSYSTEM:introduced=9.0.114,fixed=9.0.116; org.apache.tomcat.embed:tomcat-embed-core (Maven) ECOSYSTEM:introduced=9.0.114,fixed=9.0.116.

**Is there a fix for CVE-2026-29129?** Yes. org.apache.tomcat:tomcat (Maven): upgrade to 9.0.116 or later; org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.116 or later; org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.116 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-29129 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-29129?** Check whether you run Apache Tomcat, org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat-coyote (Maven) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.apache.tomcat:tomcat (Maven): upgrade to 9.0.116 or later

  ```sh
  # set org.apache.tomcat:tomcat to 9.0.116 in your pom.xml or build.gradle
  ```

- org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.116 or later

  ```sh
  # set org.apache.tomcat:tomcat-coyote to 9.0.116 in your pom.xml or build.gradle
  ```

- org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.116 or later

  ```sh
  # set org.apache.tomcat.embed:tomcat-embed-core to 9.0.116 in your pom.xml or build.gradle
  ```


## Technical details

A vulnerability in Apache Tomcat (CWE-327) occurs because the server does not preserve the configured cipher preference order during the TLS handshake. This issue affects Tomcat versions 11.0.16-11.0.18, 10.1.51-10.1.52, and 9.0.114-9.0.115. An unauthenticated remote attacker can exploit this by negotiating a connection using a weaker cipher than the administrator intended, even if stronger ciphers are available and prioritized in the configuration. This can lead to a loss of confidentiality if the negotiated cipher is susceptible to known cryptographic attacks. The issue is resolved in versions 11.0.20, 10.1.53, and 9.0.116.

## Affected products

- Apache Tomcat 9.0.114 to 9.0.115, 10.1.51 to 10.1.52, 11.0.16 to 11.0.18

## Identifiers

- CVE-2026-29129
- GHSA-69cc-cv78-qc8g

## Timeline

- 2026-04-09: disclosed
- 2026-04-09: advisory
- 2026-04-10: other: GitHub advisory reviewed

## References

- [https://api.github.com/users/aruneko](https://api.github.com/users/aruneko)
- [https://github.com/aruneko](https://github.com/aruneko)
- [https://api.github.com/users/aruneko/gists%7B/gist_id%7D](https://api.github.com/users/aruneko/gists%7B/gist_id%7D)
- [https://api.github.com/users/aruneko/repos](https://api.github.com/users/aruneko/repos)
- [https://avatars.githubusercontent.com/u/2957726?v=4](https://avatars.githubusercontent.com/u/2957726?v=4)
- [https://api.github.com/users/aruneko/events%7B/privacy%7D](https://api.github.com/users/aruneko/events%7B/privacy%7D)

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